Metallic thermometer



(No Model.)

T. L. STURTEVANT.

METALLIC THERMOMETER. No. 406,152. Patented July 2, 1889.

Wineww. fzmszzz m UNITED STATES PATENT OFFICE.

THOMAS L. STURTEVANT, OF FRAMINGHAM,,-1VIASSACHUSETTS.

METALLIC TH-ERMOMETER.

SPECIFICATION forming part of Letters Patent #0. 400,152, dated July 2,1889..

Application filed February 20, 1889. Serial No. 300,626. (No model.)

To all whom it may concern:

Be it known that I, THOMAS L. STURTEVANT, a citizen of the UnitedStates, residing 'at Framingham, in the county of Middlesex and StateofMassachusetts, have invented certain new and useful Improvements inMetallic Thermometers; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings,- and to lettersor figures of reference marked thereon,

which form a part of this specification.

This invention relates to thermometers,

- mat-ically variations of temperature, but the energy created by suchvariations can be employed practically for various mechanical pur-.

poses.

The drawings represent in Figure l a central vertical sectionalelevation of a thermometer embodying my invention. Fig. 2 repre- .sentsa plan view of a single element composed of two metals. having unequalexpansion. Fig. 3 is va modified form of arrangement.

In such drawings, A represents the instrument'as an entirety, composedof a metallic receptacle B, of any suitable shape or construction andadapted to the purposes for which the instrument is to be employed.

- Said receptacle in the present instance is open, rectangular in shape,and adapted to receive the co-operating elements G O, which are likewiseand preferably rectangular in shape. Said elements are composed of twoplates of metal a I), having unequal coeflicients I of expansion-as, forinstance, zinc and ironand these. are united in this instance by rivets.To complete the element,I prefer to give it initial curvature, therebycausing it to as sume a shape concave-convex in a section lengthwisethereof. When .so curved the convex surface portion consists of. themetal having the larger coefficient of expansion; as

zinc, while the concave portion is composedof the metal with the smallercoefiicient, as iron. The said elements are secured together by rivets00, passed through the middle parts" of them, as shown in Fig. 1, eachupwardlybent element being fastened in this way to the proximatedownwardly-bent element at their central point of contact. This keepsthem in proper position and insures their even and equal actiontogether. The elements after being united are then arranged, preferably,in couples, as shown, oppositely disposed,

and are further provided with a fiat intervening plate c; Thus when saidelements are multiplied and caused'to operate, said plates perform suchoffice that all the couples rise or fall with perfect uniformity.Surmounting said elements 0 O,and within the redeptacle B, I have placeda piston D and attached serves as the indicator in connection with agraduated s zale. (Not shown.) Moreover, a coil-spring e or itsequivalentis located between the top of the piston and.-that of thereceptacle, to insure constant. contact of said piston with "theelements-C O. In many instances gravity may be depended upon. However,in the employment of this in"trument to actuate a valve, the expansionof the plates may cause it to open,while the spring is used should be astrong one.

It will be observed that by the employment in couples of the elements 0O, which may be multiplied to any desired extent, a large movement ofthe indicator-rod may be produced with a small change in temperature.This movement is attended with considerable energy, and therefore can beusedpractically or manymechanicalpurposes. Consequently this thermometeris equally serviceable as a thermostat, since'the latter is aself-acting v apparatus for regulating temperature. Inasmuch as myinstrument is capable of exerting considerable'energy, it follovs thatthe indicator-rod (1 may be attached to a connecting-rod or lever orlevers for operating and controlling mechanism which it is desirto closethe same, inwhich event the spring 75 thereto a rod 11, which extendsupward and able should be actuated according to the temperature or theheat which influences the elements 0 0, thereby regulating thetemperature in any desired locality.

In --Fig. 3 is shown a modified arrangement of the elements, since it isnot necessary to have them placed in couples oppositely disposed; butinstead they may be disposed in any manner desired, with a plate aintervening between every element. The action of the instrument will besimilar with either method employed, and regardless of the curvature ofsaid elements.

What I desire to claim is- V 1. An instrument for measuring variationsof temperature, consisting of a series of .00- operating elements, eachelement formed of two metallic plates with unequal coefficients ofexpansion, said plates having initial curvature, arranged oppositely incouples and capableof multiplication,in combination with a pistonresting on said elements, an indicat-J ing-rod attached to said pistonand movable therewith, and a returning-spring bearing on said piston,substantially as and for the purposes herein described.

2. An apparatus for indicating variations of temperature, as hereindescribed, consisting of a series of confined metallic plates formed oftwo metals having unequal expansion, a series of flat plates alternatingwith said bimetallic plates, and a piston and indicator-rod actuated bythe expansion and contraction of said bimetallic plates, substantiallyas specified.

3. The combination, with the box B, its piston D, the rod d, and itsspring e, of a series of elements 0, composed of two metals a b, withunequal expansion, united together, and the intervening flat plates 0,between which a single bimetallic plate or pair .of plates may bedisposed, substantially as herein set forth.

In testimony whereof I affix my signature in presence of two witnesses.

THOMAS L. STUR'IEVANT. Witnesses:

N. HEATON, H. BLACKNALL.

